Compensating device for telephonic circuits.



S. G. BROWN. 4

Y COMPENSATING DEVICE FOR TELEPHONIC CRCUITS.

APPLICATION f lLn sEPT.1 9, |912.

1,149,946. 5 Patented May25,19115..

wvwpj v n SIDNEY GEORG-E BROWN, OF LONDON, ENGLAND.

COMPENSATING DEVICE FOR TELEFONIC CIRCITS.

Specification of Letters Patent. l

Patented May 25,- 191,5.

Application led September 19, 1912. Serial No. 721.282.

To /177 l/mn/ it inf/ 1] concern.'

lle it known th..- I, SmNnY GEORGE lnowx, a subject of: the, King of Great lh'ilain, residing at 4 (lrreat ,Vinchester street, in the city and county of London,

.llnglamL have invented certain newA and use'r'ul Improvements in Compensating Devices Jfor lelephonic- Circuits, of which the following is a specilication.

This invention relates to a compensating device. to he used in telephonie circuits for the purpose ol preventing sounds which enter the transmitter from appreciz'ibly yalliccting'the receiver at the same end ot' the line, the device providing the desired compensating effect without substantial loss otl current or interference with. the messages received from thc other endl of the line.

According to my invention l shunt the transmitter with a compensating coil so adjusted with relation to a coil ot' the adjacent receiver or telephonie relay as to annul the inductive ell'ect upon the receiver or relay of changes ol ein-rent due to the said transnlitter.

The compensating coil is especially useful with telephonie relays. where disturbing,r sounds a-rc liable to he greatlymagnified. lult it is also serviceable in ordinary and in long distance telephonie work. It may,

where necessary. he provided with adjustahleresislam-e. capacity and sell' induction lo permit ol' more perl'cct compensation.

'lelephonie relays may he arranged to worli in the center ol' a line with but little loss ol' eliciemgv. hy placing the primary of (he reccizing lranslormer in ,scries with [he wcondanv oll the sendingon transformer, and compensating the ell'ect. ot' the latter on the l'ormer hy means ol the compensatingr coil.

-ln order that the said invention may be clearly understood and readily carried intol eli'ect, l will describe the Same more fully with reference, to the accompanying drawings-in which:-

Figure 1 is a diagram showing the application of my compensating coil to a telephone cxnploying a telephonie relay. Figs. 2 and 3 are diagrams showing the application of the cmnpensating coil to another type of connection. Fig. -l is a diagram showing the coil applied to a telephonie relay in the middle of a long distance circuit, and Fig. 5

shows the invention applied to a double relay.

A is the telephone circuit line.

B is the transmitter.

C is the receiver.

D is the compensating coil the circuit al* of which is connected across the transmitter.

Referring lo Fig. l it will be seen that any disturlmnces due to the transmitter B causes a change of current through the coil c which if not compensated would set up a `current in the secondary receiver coil c.

The compensating shunt coil D however is wound and connected across the transmitter l so as to act in opposition to the change of current passing through the coil c and to neutralize its effect upon the secondary receiver coil c. The coil D takes only a small fraction ot the total current and consists of a large number of turns of fine wire so that the currents flowing through it produce equal and opposite effects to the currents simultaneously flowing through the coil 0, so far as disturbances arising from the shunted transmitter B are concerned. The compensating circuit may include an adjustable capacity Z and inductive resistance d to permit of more perfect compensation. 'lheI capacity Z may be provided with 'a high resistance shunt cl2. Thereceiver C is shown with ya relay c2, used for long distance telephony, when the compensating coil proves ot' special advantage owing to the great magnication of the sounds due to the relay.

Fig. 2 shows the application of the compcnsating coil to the Western Standard connection, in which an auto-transformer c* is placed in the circuit A, this auto-transformer serving in place of the two transformer coils 0 and c in the connections previously described. The circuit-A also includes a condenser a and the ,transmitter B is connected across the receiver C, the conceiver is shunted by a coil c3 and the compensating coil D acts upon this receiver -coil being connected-across the sending on transmitter B, which is under the control of the receiving transformer c, c through the relay c2. The arrangement is substantially the same as that already described in coi.-

nection with Fig. 1, excepting that the transmitter B replaces the receiver C in the relay circuit. Disturbances due to the ac tion of the sending on transmitter, which affect the receiver' coil-c at the same time causing compensating impulses in the coil D so that the receiving transformer circuit is unaiected.

, The double relay of Fig. 5 does not differ in its action from they relay .already described, but is' connected across'the tWo line Wires A. It therefore comprises two sendingon transmitters B and receiving transformers e, c and two compensating coils connected across the sending on transmitters.

In each case Where a transmitting coil is used, the compensating coil may, ifv prel ferred, be connected across only a portion of4 the transmitting coil instead of shunting the transmitter as a Whole.

What I claim andvdesire to secure by Letl ters Patent of the United States is :V

l. In a telephonie circuit, a microphonic transmitting element, a receiving element adjacent to the transmftterr and a compensatlng coil at the receiving element connected in shunt to the transmitting element and so Wound as to'annul the inductive ef feet of theklatter upon. the said receiving element. y

2. In a telephonie clreuit, a microphonic transmltting element, a receiving element adjacent tothe transmitter, a transformer for the said recelving element and a compensating coil atA the receiving element, connected in shunt to the transmitting element.

and so Wound as to annul the inductive effeet of the latter upon'the said receiving element.

3. In a telephoniel circuit, a microphonic transmitting element, a receiving element adjacent to the transmitter, a compensating coil `at the receiving element connected in shunt to the transmitting element, and adjustable capacityl and resistance in the'circuit of the compensating coil. A

4l. In a telephonie circuit, a microphonic transmitting element, a` receiving. element adjacent to the transmitting element, a com? pensating coil at the receiving element conf nected-in shunt to the transrmttingielement,

and adjustable capacity, self induction and resistance in the circuit of the compensating coil.

5. In a telephonie circuit, amicrophonic transmitting element, a receiving lelement adjacent to the transmitter, a telephonie relay-operated -by a sending on receiving 'ele ment and controlling the said transmitting element and a compensating coil at the receiving element, connected in shuntto the v transmitting element and so Wound as to annul the inductive effect of ythe latter upon theisaid receiving element.

In testimony whereof I affix my signature in presence of two witnesses.

SIDNEY GEORGE BROWN.

Witnesses: i i i ALLAN SAXTER, JAMES S. R. SMrrH. 

